Proform 3/8 x 1" Wedge Locking Header Bolt, Pack Of 12 #66753

Each PROFORM® Grade 8 Header Bolt is permanently assembled with a pair of special washers. When the bolt is torqued to 28+ ft-lbs, the washers’ super-hardened external teeth bite into and grip the bottom of the bolt head and the top surface of the header.

After being self-locked in this manner, any bolt-loosening rotation is blocked by a wedge-locking action created by the washers’ interfacing, matching cams. It’s an uphill climb: vibration that might ordinarily loosen the bolt actually increases the wedge-locking tension, securing the bolt even more.

Because this simple wedge-locking method uses tension instead of friction, contact with oil actually facilitates the wedge effect. When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.

Features:

• Grade 8 (12.9) Steel


• Hex Head Type


• 1-inch Length


• Fits GM V6, SB 265-400, Buick, Olds, Pontiac '79 and earlier, Mopar BB 383-440 exc 413, AMC V8's w 3/8" bolts


• Sold as Set of 12

Specifications :

Brand: Proform Parts

Manufacturer's Part Number: 66753

Part Type: Header Fasteners

Product Line: Proform Self-Locking Wedge Header Bolts

Fastener Style: Bolt

Thread Size: 3/8 in.-16

Head Style: Hex

Underhead Length (in.): 1.000 in.

Fastener Material: Steel

Fastener Color: Black oxide

Quantity: Sold as a set of 12.